In this archival study we used real historical stock prices to examine the hypothesis that grammatical gender assignments of a company’s name passes gender stereotypes onto the company itself, and consequently changes investors’ expectation of the stock performance. We gathered historical stock price data from Spanish speaking countries, and compared average momentum (the expectation that the current price trend will continue. i.e. what went up will keep going up, and what went down will keep going down) among the companies with masculine names, feminine names, and gender ambiguous/neutral names. We calculated momentum utilizing different lengths of observation and holding time, as well as different calculation frequencies (by days and by months) to test for robustness of the result. Across different strategies, masculine-named companies consistently display higher momentum than feminine-named companies. Moreover, disaggregating the momentum into momentums during upward trends (momentumbuy) and downward trends (momentumshort) indicates that the observed momentum return results mostly from buying past rising stocks, rather than shorting past falling stocks. Gender differences are not evident in momentumshort. Implications for the effect of grammatical gender in high-stakes situations, and future directions are discussed.